In the body, potassium has many functions, the more important of which are operating nerve impulses and contracting muscles. Potassium is present as the positively charged ion K+ and it concentrates inside cells, which is where 95% of the body's potassium is located, unlike sodium and calcium, which are more abundant outside cells. A cell membrane has millions of tiny channels through which potassium ions flow and every one is capable of transferring hundreds of potassium ions per second in and out of the cell. This activity is responsible for the transmission of nerve impulses from the brain, because it moves like a wave along the nerve fibre just as if it were an electric current.
Some channels only permit potassium to pass through, and the toxin of the black mamba kills its victim by specifically blocking them. The same result can be achieved by injecting a concentrated solution of potassium chloride into the bloodstream which prevents the movement of potassium out of the cell because there is already too much potassium on the outside pushing to get in. All body functions are affected, but none more dramatically than the heart muscle which stops beating. Murders have been committed with potassium chloride, and doctors and nurses have been known to end the lives of terminally ill patients by giving them injections of potassium chloride solution. Such injections are used in the USA to execute criminals convicted of murder.
Deadly though it can be, potassium is still a major dietary requirement, lack of which causes muscle weakness. Indeed it is not generally appreciated that the need for potassium salts in the diet is much greater than for sodium salts. The recommended daily intake is 3.5 g, whereas for sodium it is 1.5 g. Vegetarians take in a lot more potassium than non-vegetarians because potassium is abundant in all plant foods. We must have a regular supply of dietary potassium because we have no mechanism for storing it in the body, yet few people are affected by a deficiency of this metal because almost all we eat contains potassium. Some foods are particularly rich in it, such as raisins, almonds, peanuts, and bananas; one banana will provide a quarter of our daily requirement. Other common foods with lots of potassium are potatoes, bacon, bran, mushrooms, chocolate, and fruit juices.
Salt substitutes are 60% potassium chloride, 40% sodium chloride, and using this in cooking and flavouring is not life-threatening but life-saving if it reduces the amount of salt in the diet of those suffering from heart disease. There are rare cases of excess ingestion by humans proving fatal, including one person who ate half an ounce of this salt (14 g), although the normal amount of potassium chloride needed to cause a serious toxic response is more like 20 g.
Potassium chloride was the chosen murder weapon of one notorious serial killer whose victims were babies and young children. She was Beverley Allitt who was employed as a children's nurse at the Grantham and Kesteven General Hospital in Lincolnshire, England, and over a period of ten weeks she injected ten children with potassium chloride. Thankfully she only succeeded in killing four of them.
Although Allitt trained to be a nurse, she had repeatedly failed her nursing exams, but in February 1991 she was taken on temporarily at the local hospital because they were short staffed. Her first victim was a seven-week-old baby, Liam Taylor, who was admitted to the children's ward on 21 February suffering from congestion of the lungs. His parents were reassured by Allitt that their baby was in good hands, but when they returned to visit him a few hours later they were informed that he had been rushed into emergency care, although he was now recovering. The parents asked if they could stay the night at the hospital and were shown to a bedroom specially assigned for this purpose, happy in the knowledge that Allitt had elected to work a night shift specially to be near Liam in case he needed help quickly, which around midnight he did. Allitt suddenly signalled for help because Liam's heart had stopped beating. Although doctors and nurses struggled to revive the baby, it was in vain.
On 5 March 1991, an 11-year-old boy, Timothy Hardwick, who suffered from cerebral palsy, was admitted to the hospital after a severe epileptic fit and was put under Allitt's care. She was particularly solicitous in attending to the boy, but soon after she was left alone with him his heart stopped beating. She summoned help immediately, but despite the efforts of a pae-diatric specialist who rushed to the boy's aid, he died. An autopsy was carried out, but found no obvious cause of death, and so his death was recorded as due to epilepsy.
On 10 March, a 1-year-old girl, Kayley Desmond, was admitted to the children's ward suffering from lung congestion. Allitt was assigned to her care and although the little girl appeared to be getting better she suddenly went into cardiac arrest. The crash team at the hospital managed to revive her and she was then rushed to the larger hospital at Nottingham where she recovered fully. Doctors there noticed that she had a puncture below her armpit, and this came to their attention because there was a bubble of air under the skin. We now know that Allitt had injected potassium chloride solution from a partly filled needle and before she had removed all the air in the syringe. (It was little wonder that she had failed her nursing examinations.)
Frustrated at her failure to kill Kayley, Allitt changed her modus operandi and decided to try insulin as her weapon of attack. On 20 March, 5-month-old Paul Crampton came to the hospital with severe bronchitis. He suddenly went into a coma but the doctors revived him and noted that his blood sugar level had fallen dangerously low, this being the effect that insulin can have. Despite the efforts of the medical staff, Paul had two further attacks and so he too was sent to Nottingham for more specialist care - and survived.
The next day Allitt returned to using potassium chloride and her victim was 5-year-old Bradley Gibson: he suddenly suffered a heart attack, but the doctors were able to save him. When he had another heart attack later that night he too was despatched to Nottingham and he too recovered. It was the same with her next victim, 2-year-old Yik Hung Cha, who had fallen from a window and fractured his skull. He suffered in exactly the same way as Bradley, and he too was saved by being rushed to Nottingham. Allitt's next victims were not so lucky.
Katie and Becky Phillips were twins who had been born prematurely and had been looked after at the hospital before being sent home in March 1991.
On i April Becky was readmitted to the children's ward suffering from gastroenteritis. Allitt was responsible for her care but the baby went into convulsions that evening, which a doctor diagnosed as being caused by her illness. Her parents stayed by her bedside watching over her but she died in the night. An autopsy revealed no obvious cause of death. Then her twin sister Katie was admitted to the hospital and in the course of the next two days she had two heart attacks, during which her parents were impressed with the strenuous efforts Allitt made to save their daughter's life. However, she was transferred to Nottingham where they discovered that five of her ribs were cracked (probably as attempts had been made to re-start her heart) and that her brain was damaged through lack of oxygen. However, Katie's parents were so grateful that her life had been saved, and thinking this was due to the prompt action of Allitt, they asked the nurse to be the baby's godmother, and this she did when the child was christened a few days later.
Meanwhile other children in Allitt's care continued to be struck down with unexpected complications, but were saved thanks to the efforts of other nurses and doctors. At first the hospital staff suspected that a virus was the cause and they had the children's ward decontaminated, but it was only when that had no effect that they began to suspect that human malevolence was behind these mysterious attacks and that pointed to the only person who was always around when they happened: Allitt. Their suspicions were soon to be confirmed.
Claire Peck was in hospital suffering from an asthmatic attack so severe that doctors had inserted a tube into her throat to help her breathe. The little girl suddenly had a heart attack and Allitt was the only nurse in the ward at the time. The emergency team rushed to help the young girl and revived her, but soon after they left the child, again under Allitt's sole care, she immediately had another attack. This time they could not revive her and Claire Peck died. An autopsy now included analysis of her blood and this showed an unnaturally high level of potassium. The hospital authorities called in the police, and they arrested Allitt.
Allitt came to court in March 1993 and after a trial lasting nearly two months she was found guilty and given i3 life sentences, the highest such penalty handed down to a woman. Why did she do it? The answer would appear to be that she was suffering from a disorder called Munchausen's syndrome by proxy, a rare mental state was first diagnosed in 1977. A person manifesting this condition will maliciously attack those who are in his or her care.
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